The quality, state, or degree of being disregardful; the characteristic of showing lack of proper attention or respect.
From disregardful + -ness (suffix creating abstract nouns of quality, from Old English 'ness'). This creates four levels of related words: disregard, disregardful, disregardfully, disregardfulness.
English's system of stacked suffixes (dis-regard-ful-ness) creates incredibly long words with subtle meaning differences, which is why English has such a vast vocabulary compared to simpler languages that prefer shorter building blocks.
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